.TH MACH-FILE 3
.SH NAME
crackhdr, uncrackhdr, mapfile, mapproc, detachproc, ctlproc,
procnotes \- machine-independent access to exectuable files and running processes
.SH SYNOPSIS
.B #include <u.h>
.br
.B #include <libc.h>
.br
.B #include <mach.h>
.PP
.ft B
.ta \w'\fBxxxxxx'u +\w'xxxxxx'u
int	crackhdr(int fd, Fhdr *hdr)
.br
void	uncrackhdr(Fhdr *hdr)
.PP
.ft B
int	mapfile(Map *map, ulong base, Fhdr *hdr)
.br
int	mapproc(Map *map, int pid)
.br
int	detachproc(int pid)
.br
int	ctlproc(int pid, char *msg)
.br
int	procnotes(int pid, char ***notes)
.SH DESCRIPTION
These functions parse executable files and 
provide access to those files and to running processes.
.PP
.I Crackhdr
opens and parses the named executable file.
The returned data structure
.I hdr
is initialized with a machine-independent description
of the header information.  The following fields are the
most commonly used:
.TP
.B mach
a pointer to the
.B Mach
structure for the target architecture
.TP
.B mname
the name of the target architecture
.TP
.B fname
a description of the kind of file
(e.g., executable, core dump)
.TP
.B aname
a description of the application binary interface
this file uses; typically it is the name of an operating system
.PD
If the global variable
.I mach
is nil, 
.I crackhdr
points it to the same 
.B Mach
structure.
.PP
.I Mapfile
adds the segments found in
.I hdr
to
.IR map .
If
.I hdr
is an executable file, there are typically three segments:
.IR text ,
.IR data ,
and a zero-backed
.IR bss .
If
.I hdr
is a dynamic shared library, its segments are relocated by
.I base
before being mapping.
.PP
If
.I hdr
is a core file, there is one segment named
.I core
for each contiguous section of memory recorded in the core file.
There are often quite a few of these, as most operating systems
omit clean memory pages when writing core files
(Mac OS X is the only exception among the supported systems).
Because core files have such holes, it is typically necessary to 
construct the core map by calling
.I mapfile
on the executable and then calling it again on the core file.
Newly-added segments are mapped on top of existing segments,
so this arrangement will use the core file for the segments it contains
but fall back to the executable for the rest.
.PP
.I Mapproc
attaches to a running program and adds its segments to the given map.
It adds one segment for each contiguous section of 
mapped memory.
On systems where this information cannot be determined, it adds
a single segment covering the entire address space.
Accessing areas of this segment that are actually not mapped
in the process address space will cause the get/put routines to return errors.
.I Detachproc
detaches from a previously-attached program.
.PP
.I Ctlproc
manipulates the process with id
.I pid
according to the message
.IR msg .
Valid messages include:
.TP
.B kill
terminate the process
.TP
.B startstop
start the process and wait for it to stop
.TP
.B sysstop
arrange for the process to stop at its next system call,
start the process, and then wait for it to stop
.TP
.B waitstop
wait for the process to stop
.TP
.B start
start the process
.PD
.PP
.I Procnotes
fills
.BI * notes
with a pointer to an array of strings
representing pending notes waiting
for the process.
(On Unix, these notes are textual descriptions
of any pending signals.)
.I Procnotes
returns the number of pending notes.
The memory at
.BI * notes
should be freed via
.IR free (3)
when no longer needed.
.SH SOURCE
.B /usr/local/plan9/src/libmach
.SH "SEE ALSO"
.IR mach (3),
.IR mach-map (3)